25% valedictorians.
Average SAT 740M, 750R, 740CW (highest, with HMC, of any LAC. Only major universities with higher SATs are HYPM and Cal Tech)
90% in top 10% of class.
15.8% acceptance rate (lowest of any major LAC).

5th highest endowment per student of any school in the country (behind HYP).
Plus SoCal weather and access to LA.

Maybe not a perfect match for the OP, but still most underrated IMHO.
Yeah, I'm biased. My D will be in the class of 2011.

I tend to think that Claremont as a whole is underrated (in the sense of being largely unknown, but also regularly undervalued). There are four other undergrad colleges in the consortium, not all of whom can boast the statistics shared by SarahsDad, and yet each of whom provides remarkably similar (no...not claiming identical!) opportunities, both social and academic.

I think that the consortium as a whole is the best aspect of any Claremont school, but sometimes gets mistakenly pushed aside in the interest of its most highly ranked members.

In terms of easy admission, which seems to be part of the OP's criteria, Claremont doesn't really fit the bill. Even the schools with lower stat standards are hard to call safeties because they're looking for close fits, not just numbers. That said, the applicant pools are still relatively small, and things are only on the rise...